Pressure-retentive receptacle, especially for bulk-carrying vehicles



PRESSURE-RETENT IVE RECEPTACLE, ESPECIALLY FOR BULK-CARRYING VEHICLES Filed April 20, 1967 Dec. 31, 1968 F GRAMLICH 3,419,310

m mroy: Frifz Gram Iich BY wAgf Attozqey nited States ABSTRACT OF THE DISCLOSURE Pressure-retentive receptacle (e.g. for bulk-carrying vehicles) having a right-circular central cylinder and a pair of quarter-spherical end members welded to and smoothly merging with the central member, the quarterspherical end members being obliquely cut away and having a lower edge inclined obliquely outwardly from the center of curvature of this quarter sphere and the intersection of the horizontal median longitudinal plane of the receptacle with the surface of the quarter sphere; a bow-shaped member is welded to this lower edge of the respective quarter-spherical shell member and to the corresponding downwardly converging conical outlet duct, and has a greater curvature in the vertical plane than that of the quarter-spherical shell member. The quarter-spherical shell member has a radius of curvature identical with that of the central member; the bow-shaped member extends approximately rectilinearly in continuation of the respective outlet duct to the respective lower edge of the quarter-spherical shell and merges smoothly therewith.

My present invention relates to pressure-retentive receptacles for the transportation of flowable materials and more particularly to an improved receptacle structure for storage uses and also suitable for use in bulk-carrying vehicles such as tank trucks and railroad cars.

While bulk carriers of various shapes have been proposed heretofore and some are designed to convey or transport flowable material from one location to another under pressure, the design of such structure has been relatively complex and their construction relatively complicated by the interplay of the desiderata for such systerns, For example, the outlets of the bulk carrier must be such that pulverulent solid materials can flow from the storage bin or container without obstruction and without budging or otherwise interruption of discharge except as controlled by the outlet orifice. Secondly, the interior of the vessel must be smooth-walled and free from dead spaces (e.g. nooks and crannies, blind passages) or the like in which some bulk material may remain after discharge of the major portion of the load. Thirdly, the assembly of the system must be pressure-tight and free from highly stressed or weakened portions, sharp corners, irregular junctions or the like, all of which limit the structural integrity of the system. Fourthly, there must be maximum utilization of the space and weight of the receptacle.

In prior systems in which pressurized receptacles have been used as bulk carriers in tank cars for railroad purposes or as semitrailers for automotive applications, it has been proposed to provide a generally cylindrical main portion having downwardly tapered and inwardly sloping ducts whose outer walls merge with dome-shaped end members, the latter closing the cylinder at each end. These constructions were not always as free as is desired of sharp corners, sudden turns, blind passages etc. within the receptacle and could not be assembled inexpensively, with ease, and with the necessary degree of pressure retentivity and strength.

It is, therefore, the principal object of the present invention to provide an improved receptacle construction, particularly suited for the transportation of bulk materials in flowable form, wherein the aforedescribed disadvantages are avoided and the system can be assembled with less difliculty and with greater structural integrity than has been possible heretofore.

A further object of this invention is to provide a bulkcarrying vehicle for the transportation of flowable solid materials which is free from unduly stressed portions, can be emptied rapidly and efliciently and has a high capacityto-weight and capacity-to-volume ratio.

These objects and others, which will become apparent hereinafter, are attainable with a bulk-transport vessel which comprises a substantially right-circular cylindrical central member having a generally horizontal axis and formed at the bottom with a plurality of downwardly tapering generally conical outlet ducts, and a pair of quarter-spherical end members or domes closing the ends of the central member and merging smoothly into the outlet ducts. While I have found that it is possible to connect the end members to the central members by means of wedge-like wall portions converging downwardly to a point, thereby orienting the members somewhat o-bliquely such that their curved end faces lie approximately in continuation of the wall of the outlet duct, it is often difiioult to assemble such structures and, indeed, it may be difiicult to ensure full flowability of the bulk material and elimination of dead space.

This disposition of the end members in continuation of the wall of the outlet ducts is desirable because the transition established between the outlet duct and the domed end member is favorable in withstanding pressure. The opening angle of the outlet duct must not exceed a predetermined and ascertaina-ble magnitude because otherwise the fiowable material may not pass properly through the ducts. Since, for the same reasons, the pressure contamer cannot project beyond the inner aperture of the conical outlet ducts, it is advantageous, for optimum utilization of the container capacity and the smallest possible number of outlets to extend the wall of the conical outlet duct to the uppermost parts of the container.

It is, therefore, desirable (for obtaining the largest possible capacity) that the wall of the outlet duct, which has a small inclination under optimum conditions, be extended upwardly to the greatest extent in order that the upper end portions of the container project as far as possible. If, however, this wall is brought to the very top of the pressure container, an edge or junction with a very small radius of curvature is produced; this transitron requires special reinforcement because it cannot bear as much pressure loading as surfaces with a larger radius of curvature. I have now found that these objects can be attained in a pressurizable container Or vessel, especially when the latter is used as a bulk-goods carrier in the form of a tank truck or railroad car, when the upper portion of each member consists of a quarter-spherical shell member which has the same radius as the cylindrical central member and is cut away, biased or bevelled obliquely outwardly and upwardly only over a part of the quartersphere mirror symmetrically with respect to the vertical longitudinal plane through the center of the cantral member, i.e. the vertical median longitudinal plane of the vessel.

Reference is made here and below to quarter-spherical shell members and the like, but this phrase must not be understood in a strictly mathematical sense. The phrase quarter circular shell members is intended to include also shapes which are derived from a strictly mathematical quarter-spherical shape by expansion, compression and 'bending operations of a minor nature so as to have no noticeable elfect with respect to the pressure distribution or pressure-sustaining capability of the vessel.

Such a quarter-spherical shell member has, according to the invention, the same or substantially the same radius of curvature as the right circular cylindrical central member with horizontal axis, and if the wall thickness and the assembly are the same, it can therefore be pressurized to the same extent as the central member. Such a quarterspherical shell member can also be produced very easily by mass production methods from a semi-spherical member by division along the intersection with the hemispherical shell with the diametral plane of the latter, the center line and by subsequently cutting or bevelling the resulting shell members obliquely.

In the region of the horizontal plane through the center of the pressure container, the lowermost edge region of the quarter-sphere merges smoothly by way of an intervening curved bow-shaped member into the wall of the outlet duct having any desired optimum angle of inclination.

A further feature of the invention resides in the provision of a bow member which extends, mirror-symmetrically with respect to the perpendicular longitudinal median plane, from the region of the oblique cut-away or bevel (lower edge of the quarter-spherical shell) and the region lying therebelow in the continuation thereof to the wall of the respective outlet duct and is so welded to the adjacent wall portions that smooth, substantially continuous transitions are produced, the bow member being curved more strongly in the vertical longitudinal median plane in the region of the oblique cut-away than the quarter-spherical shell member, and extending therebelow in a straight line in the direction towards the outlet duct and in the continuation thereof.

At the two lower edge portions of the quarter-spherical shell member which lie in the horizontal longitudinal plane through the center of the pressure container and butt against the end edges of the central member, there remains a triangular area which is filled according to this invention, while it is possible to extend the quarter-spherical shell "member into this triangular area; this would mean that it is no longer possible to produce two quarterspherical shell members from one semi-spherical shell. For this reason I provide curved right-angled triangular members which are welded, one on each side of each end member, along one short side or leg of the triangle to the lower edge of the quarter-spherical shell member, along the other short side or leg to the edge of the central member, and along the hypotemuse to the respective edges of the bow member and the wall of the outlet duct forming a substantially continuous smooth transition therewith. Since in this case relatively small triangular members are concerned, the production of these triangular members does not create any problems.

In pressure containers according to the invention, the conical walls of the outlet ducts inclined at the most favorable opening angle, are continued, at both container ends, above the horizontal median plane so that the upper portions of the curved end members project away from both ends far beyond the outlet apertures at the lower end of the outlet ducts in a manner desirable for a large capacity and a pre-selected number of outlet ducts.

The pressure containers may be used as stationary receptacles or as transport vessels. In all cases, supports are provided in such manner that there is sufficient space between the outlet ducts and a supporting surface for accommodating connecting means. Preferably a support is attached to each end member and projects beyond and downwardly from the associated container end. The supports may he stands by means of which the pressure container can be supported or mounted on the ground or on a vehicle platform or on a vehicle chassis. If the pressure container is used in conjunction with a tractor, the one support may be used for receiving the tractor coupling whereas the other support may be adapted for attachment to the trailer constituting the rear axle unit.

The above and other objects, features and advantages will become more readily apparent from the following description, made with reference to the accompanying drawing, in which:

FIG. 1 is a side-elevational view of a pressure container according to the invention, constructed as a semi-trailer; and

FIG. 2 is the view in the direction of arrow II in FIG. 1, the rear-axle unit or truck being omitted.

The semi-trailer of the drawing is provided with a rigid-circular cylindrical central member 1 to which are attached at the bottom, one behind the other, two conically downwardly tapering outlet ducts, 2, 3 which have outlet apertures 4, 5 and to which closable outlet members 6, 7 are joined for connecting pneumatic discharge pipes to the receptacle. Ot the top of the central member 1, there are provided two inlet openings 8, 9 which are disposed one behind the other, each being closable by a pressure-tight cover 10, 11. To each end of the central mem her there is welded above the horizontal longitudinal median plane HMP a quarter-spherical shell member 12, 13 which is cut away obliquely at the bottom along a line 12', 13', extending upwardly and outwardly and lying in the respective intersection plane LOP and ROP between the center of curvature 12", 13" and the intersection 12a, 13a of the horizontal plane with the quarterspherical surfaces; this cut or bevel does not extend over the whole length of the radius r of the quarter-spherical shell member. The radius of curvature r of the two quarter-spherical shell members 12, 13 is the same as the radius of the central member 1. Reference numerals 14- and 15 denote two bow-shaped members which are welded to the quarter-spherical shell members 12, 13 symmetrically with respect to the vertical longitudinal median plane VMP, so that at each end a pressure-retentive curved end member 18, 19 is produced. The bow-shaped members 14, 15 are curved more strongly in the vertical median planethat is to say in the plane of the paper in FIG. 1in the region of the oblique cut or bevel than the quarter-spherical shell members; the bow members then extend in straight-line continuation of the walls of the outlet ducts 2 and 3, respectively.

On each side below the lower edge of the quarterspherical shell members 12, 13, there remains an open triangular space which is closed by one of four curved right-angled triangular members (three of which are shown at 16, 17 and 26).

The walls of the end members 18, 19, that is to say the walls of the quarter-spherical shell members 12, 13, the walls of the bow-shaped members 14, 15 and the walls of the triangular members 16, 17 and 26 as well as the walls of the central member 1 and the wall portions of the outlet ducts 2, 3 disposed at the ends, merge smoothly into each other without sharp bends. The individual parts consist of sheet metal and are butt-welded to each other to attain smooth continuously curving transitions without sudden changes of direction. The straight surface line 20, 21 lying in the vertical plane through the center of the outlet duct continues rectilinearly into the region of the respective end member 18 or 19 disposed at the same end, and extends nearly to the upper end of the bow-shaped member 14 or 16, respectively, that is to say beyond the horizontal median plane HMP.

A support member 22, 23 is welded to each end member 18, 19, respectively. In the present example, the sup port member 22 serves for receiving a tractor or truck coupling 24, where as the support member 23 is adapted to engage the trailer unit incorporating the rear-axle unit bogie or truck 25.

The invention described and illustrated is beileved to admit of many modifications within the ability of persons skilled in the art, all such modificatons being considered within the spirit and scope of the appended claims.

I claim:

1. A pressure-retentive receptacle for the transportation of flowable materials, comprising:

a substantially circularly cylindrical central member having a generally horizontal axis and formed at the bottom of said member with a plurality of downwardly tapering generally conical outlet ducts and a pair of end members located at least at the opposite axial ends of said central member and secured to said central member and closing same at said opposite axial ends, the wall surfaces of said central member merging smoothly into the wall surfaces of said end members and said ducts merging smoothly into the wall of said members, each of said end members having an upper shell portion with a configuration corresponding to that of a quarter sphere with a radius equal to that of said central member, a lower edge of each shell portion lying generally in a respective plane inclined obliquely outwardly and upwardly from the horizontal median longitudinal plane through said central member and intersecting the latter between the center of the respective quarter sphere and the surface thereof, and

a bow-shaped portion secured to and merging smoothly with the respective quarter-spherical shell portion along the respective lower edge and between the latter and respective outlet duct, said bow-shaped portion having a curvature in excess of the curvature of the shell portion in the region of the respective lower edge and extending approximately rectilinearly in continuation of the respective outlet duct to the respective lower edge.

2. The receptacle defined in claim 1, further comprising a pair of curved triangular shell members having right-triangular outlines disposed symmetrically on opposite sides of the vertical longitudinal median plane of each end member, said triangular members being each welded at one leg of the triangle to the lower edge of the respective shell portion at the junction thereof with said central member, Welded at another leg of the triangle to said central member at the corresponding junction thereof with the respective shell portion, and welded at the hypotenuse of the trinagle to the respective bowshaped portion and outlet duct with a smooth transition between said members and said portions at each of the welds.

3. The receptacle defined in claim 1, further comprising a respective support member secured to and projecting downwardly and outwardly from each of said end members.

4. The receptacle defined in claim 3 wherein the support member of one of said end members is provided with a wheeled truck and the support member of the other end member is provided with means for connecting said receptacle to a towing vehicle.

5. The receptacle defined in claim 4 wherein only two such outlet ducts are provided, one at each of said receptacle, said outlet ducts lying below said central member and being welded thereto, each quarter-shaped shell portion being welded to said central member and to the respective bow-shaped member.

6. The receptacle defined in claim 5 wherein said quarter-spherical shell portions of said end members are formed by obliquely bevel-cutting a quarter-spherical shell segment divided from a hemispherical shell.

7. The receptacle defined in claim 6, further comprising means atop said central member for introducing said flowable material into the interior of the receptacle.

8. The receptacle defined in claim 7 wherein said central member is a right-circular cylinder.

9. The receptacle defined in claim 8 wherein each of said quarter-shpherical shell portions has another lower edge lying along the horizontal longitudinal median plane of said central member and extending from the junction of the respective shell potrion with said central member to the oblique lower edge of the respective shell portion.

10. The receptacle defined in claim 9 wherein the lower edges of each shell portion are symmetrical with respect to said vertical longitudinal median plane.

References Cited UNITED STATES PATENTS 1,274,614 8/1918 Sherman 248 3,139,286 6/1964 Johnson 280--5 FOREIGN PATENTS 1,325,973 3/1963 France.

813,425 5/1959 Great Britain.

RICHARD J. JOHNSON, Primary Examiner.

US. Cl. X.R. 

